## Basic units of water measurement

There are two basic units of water measurement from a water management perspective.  For water that is in motion, cubic feet per second (cfs) is the unit of measure.
For water that is stored or impounded, the acre-foot (af) is how water is measured.

#### Cubic feet per second (cfs)

1 cubic foot = 7.4805 gallons.
1 cubic foot per second = 7.4805 gallons flowing by a particular point in 1 second.
1 cfs = 1.983 acre-feet per day = 646,320 gallons = 2447 cubic meters of water.
1 cfs is equivalent to 448.8 gallons of water flowing per minute.
1 cfs will produce 724 acre-feet of water per year.
1 cfs = 38.4 miner’s inches of water.

#### Acre-foot (af)

1 acre = 43,560 square feet.
1 acre-foot = 43,560 cubic feet.
1 acre-foot = 325,851 gallons of water = 1233 cubic meters of water.
1 acre-foot = 0.504 cfs/ day.

#### Other conversions

1 US gallon = 0.1337 cubic feet = 3.79 liters.
1 Million gallons = 3.07 acre-feet = 1.547 cfs per day.
1 gallon of water weighs 8.33 lbs.
1 cubic foot of water weighs 62.4 lbs.
1 part per million = 1 milligram per litre = 8.35 lbs per million gallons.
1 square mile = 640 acres.
1 million gallons per day = 694.4 gallons per minute.